Rocket Lab, a sounding rocket and launch vehicle company co-located in the U.S. and New Zealand, is preparing to begin testing a smallsat launcher dubbed Electron that would use battery-powered turbomachinery and other innovations to hold the cost per mission below $5 million.
The company, which received U.S.funding before branching into commercial development, unveiled its Rutherford engine at the annual Space Symposium in Colorado Springs. The engine uses high-performance brushless DC electric motors to drive its liquid oxygen and kerosene turbomachinery, drawing power from lithium polymer batteries. The approach, says CEO Peter Beck, eliminates the complex valves and other plumbing required to use hot gas to turn turbomachinery, boosting efficiency from 50% for a typical gas generator cycle to 95%.
“For us it was really about decoupling that thermodynamic problem,” Beck says. “And the beauty with an electric turbopump is that it takes that really complicated problem and turns it into software.”
Each Rutherford engine has two electric motors the size of a soda can, Beck says, one for each propellant. The small motors generate 50 hp while spinning at 40,000 rpm, “not a trivial problem,” he says.
“The battery technology is also a little bit special,” Beck says. “We’re drawing huge currents and huge energies from those batteries to provide the energy, but really it just provides such a simplified and efficient system.”
The efficiency is needed for the company’s business model, which foresees customers with payloads weighing as much as 100 kg (220 lb.) launching into 500-km (310-mi.) Sun-synchronous orbits or to inclinations as low as 46 deg. The payloads can be readied for flight at the customer’s own facility and then shipped to the launch site, which is under construction in New Zealand at a location Beck says is still “a closely guarded secret.”
Beck says the company has about 30 “commitments” from customers.
A former Crown Research engineer, New Zealander Beck established Rocket Lab with the support of seed-investor Mark Rocket, an Internet entrepreneur who changed his name from Mark Stevens.
“In 2009, we launched R-1, our first sounding rocket, on a suborbital ballistic arc,” Beck says. “That got the attention of agencies in the U.S., particularly.”
Rocket Lab subsequently studied and tested propellant and launcher technologies for Darpa,and the U.S. Operationally Responsive Space Office.
“In 2013, the company reached a crossroads,” says Beck. “Did we want to follow the road of being a U.S. defense contractor? Or did we want to get into the commercialization of space—which is always what I wanted to do? So we chose the latter.”
The company secured additional funding in late 2013 from the New Zealand government under the Callaghan Innovation Growth Grants program, and since then “we have been flying under the radar for about a year working on the development of the Electron launch vehicle,” Beck says. The Electron is “the crux of the project and is aimed at what is expected to be a huge growth of 60% or more in the small satellite business over the next five years,” he says.
The company is banking on the lightweight structure of its two-stage vehicle and the power-to-weight efficiency of the Rutherford engine to make a cost breakthrough in the small satellite launch market. Rocket Lab is targeting a cost per launch of $4.9 million, which it says will reduce the average orbital delivery costs by 95% versus the current launch infrastructure and its large reliance on ride-share payloads.
In another effort to increase efficiency and hold down cost, Rocket Lab is building the regeneratively cooled engine using three-dimensional, additive-manufacturing techniques that include laser and electron-beam sintering, with Inconel and titanium powder as the feed stock.
Nine of the engines will be used to power the 59-ft.-tall Electron vehicle, which will have a total combined thrust of 27,000 lb. at liftoff, with a targeted peak thrust of 34,000 lb. during ascent. The second stage will be powered by a 4,000-lb.-thrust vacuum variant of the Rutherford engine, essentially identical to the main-stage engine but with an extended nozzle.
Beck says that commonality extends down to the fastener level, with standardized parts used wherever possible to lower costs. For efficiency at the launch site, the Electron upper stage is designed for independent payload integration before it is literally bolted onto the top of the main stage with four bolts.
“The first flight is scheduled for the end of this year and the program is pretty mature,” Beck says.